Update Compendium and/or share spells through games

Hello everyone!  I know that this question has probably be done a lot of times, sorry if I repeat. 1) There is a way to add objects, spells, monsters... to the compendium? 2) After that I add some spells on a NPC or PC I want to, there is a way to use those spells for another character without writing them from the beginning? 3) There is a way to share Hangouts through games? It seems I can only share PGs I create. Thanks to the ones who will answer me.

1) No, you can't. Custom compendiums are on the long term plans though. 2) In theory you could have an API to transfer it between characters, but other wise I'd say no. 3) Hangouts? PGs? What are these? Doesn't ring any bells, in context of Roll20.

3) Oh sorry! My bad. I would like to say handouts and PC.  Thank you for your answers

If you have a series of handouts you are likely to use all the time and aren't always running modules, create a base game that you don't play.  Set up all your preferred handouts, npcs, rollable tables, global macros, etc., and then copy that game any time you start something new.  You can move characters through the character vault, but there isn't an easy method for handouts at the free or plus level. If you ever upgrade to a pro sub, there is the transmogrifier that allows you to move handouts, maps, characters, decks, and rollable tables from game to game.